Many advanced systems are sensitive to vibrations and other disturbances. Excessive disturbances can introduce errors into the system and shorten the lifespan of systems. In some cases, the vibrations and other disturbances are periodic in nature. Disturbances are periodic when they follow a pattern that repeats over time. Periodic disturbances can have many causes. For example, many mechanical systems can produce periodic disturbances. One specific example, a rotating shaft, commonly found in many different mechanical systems, can create a transverse torque disturbance at harmonics of the shaft's rotational frequency. These periodic disturbances created by the mechanical system can negatively effect the operation of the overall systems.
Vibrations and other disturbances are particularly problematic in space systems, such as satellites. Vibrations in satellites can introduce a variety of errors and dramatically reduce the accuracy of the satellite. Many satellites include mechanical elements that create periodic disturbances. For example, some satellites include antennas, solar arrays or other bodies that rotate and can create a periodic disturbance. Some satellites include pumps, such as the ones in cryocoolers, which can create periodic disturbances.
In many satellites the vibrations caused by these mechanical systems can be unacceptable. For example, satellites that are required to accurately orient themselves at a precise attitude or point a payload precisely are particularly vulnerable to vibrations and other disturbances that introduce jitter.
Several different approaches have been used to reduce the effects of vibrations and other disturbances. These approaches include the use of passive devices, such as tuned-mass dampers and vibration isolators. Additionally, some active devices have been employed, such as electromechanically actuated struts, to attenuate or cancel these disturbances. Unfortunately, these past solutions have had several limitations. For example, passive devices typically eliminate only part of the disturbance. Past active devices, while generally being more effective have also generally had excessive power consumption and excessive weight, and have been computationally demanding.
Thus, what is needed is an improved system and method that reduces the impacts of periodic disturbances with out requiring excessive weight, computation and power consumption.